Google Inc. has leased the former headquarters of Palm Computing Inc. in Sunnyvale, demonstrating that the No. 1 search advertising company's appetite for real estate shows no signs of abating — and showing again how the technology industry recycles the corpses of once-prominent companies.

The lease of the PalmPilot maker's former two-building, 285,000-square-foot project in Sunnyvale brings Google's holdings in the city to well over 1 million square feet.

Sources familiar with the transaction said Google leased the complex at 950 and 1000 W. Maude Ave. last week. It's the first Google deal in Sunnyvale outside of Technology Corners, the 949,000-square-foot office campus the company leased from the Jay Paul Co. last year.

"It just shows Sunnyvale continues to be a magnet, and seen as the heart of Silicon Valley for these high-profile companies," said Connie Verceles, economic development director for the city.

It also represents a recurring theme in the history of Silicon Valley technology and business, as ascendent companies overtake the offices of the Valley's once glittering stars. Palm, which in September 1999 had 80 percent of the market share for handheld computers, went public in March 2000 and saw its market cap soar to $54 billion -- an amount bigger than General Motors.

Palm's prospects were up and down for the next ten years: its Treo line of smartphones was a pioneer years before the iPhone debuted, but it rapidly lost market share to Apple and, after Android debuted, Google. In 2010, Hewlett-Packard bought Palm for $1.2 billion, but by August 2011 HP had shut down the Palm hardware business and stopped work on Palm's WebOS operating system.

The project Google just leased was built in 1999 by Jay Paul Co. and was originally occupied by Philips. Palm took it over in 2005, the same year that the property's ownership traded to an affiliate of Deutsche Bank. When HP bought Palm, it acquired Palm's real estate leases as well.

HP stayed put, renewing its lease through 2014, but the Palo Alto-based tech giant has been moving its employees to other offices it has leased recently (including at Sunnyvale's Moffett Towers), and I'm told Google's deal was direct with Deutsche. I couldn't learn the length of term or the rent; HP declined to comment, as did Google.

The Google transaction is significant because it shows Google's Technology Corners deal wasn't the extent of its interest in Sunnyvale. Google is currently building out the interiors of some of the office space it leased in that project, which is located north of Highway 101 in the Moffett Park area. The Palm/HP site is south of 101 in Sunnyvale's Peery Park, where Apple has also been expanding its footprint.

Google's expansion has been breathtaking for commercial real estate pros, with the company becoming the most active buyer and lessee in Palo Alto, Mountain View and Sunnyvale by far. It is expected to close soon on a 400,000-square-foot campus at 700 E. Middlefield in Mountain View, paying a rumored $250 million. And of course, it's been chosen to lease Moffett Federal Airfield from the government, though the deal is not yet complete.

Here is how tech analyst Rob Enderle put it to me earlier this month, explaining the space grab: "They're in everything from longevity research to self-driving cars. They've got wearables growing. Their drone business could take off. Robotics could be bigger than PCs and smartphones combined and squared. A lot of these things they're going into are high growth, and if they take off, Google is expanding ahead of that."

The deal takes one more big space off the market in Sunnyvale, which is good news for developers of new product and investors who are rehabbing spaces. The city's total vacancy rate is now 6.8 percent, according to Cushman & Wakefield.

It's the largest office lease so far this year, and a sign that second-quarter activity levels are increasing despite a lackluster Q1. Google could fit more than 1,400 employees there, assuming one Googler for every 200 square feet.